Methyl-mercury (CH₃Hg⁺) and ethyl-mercury (C₂H₅Hg⁺) have much higher toxicity than Hg²⁺ and can be more easily accumulated by organisms to form severe bioamplification. Hence, the specific and on-site detection of CH₃Hg⁺ and C₂H₅Hg⁺ in seafood is of great significance and a hard challenge. We herein designed two T-rich aptamers (H_T5 and H_T7) for specifically recognizing CH₃Hg⁺ and the total of CH₃Hg⁺ and C₂H₅Hg⁺, respectively. In the presence of all Au³⁺, Ag⁺, and T-rich aptamer, CH₃Hg⁺ and C₂H₅Hg⁺ specifically and preferentially bind with aptamer and thus induced the formation of alloy Ag–Au nanoparticles after reduction, which led to the color change in solution. This provided a sensing platform for the instrument-free visual discrimination and detection of CH₃Hg⁺ and C₂H₅Hg⁺. By using H_T5 as probe, the method can be used to detect as low as 5.0 μM (equivalent to 1.0 μg Hg/g) of CH₃Hg⁺ by bare eye observation and 0.5 μM (equivalent to 100 ng Hg/g) of CH₃Hg⁺ by UV–visible spectrometry. By using H_T7 as probe, the method can be used to detect the total concentration of CH₃Hg⁺ and C₂H₅Hg⁺ with a visual detection limit of 5.0 μM (equivalent to 1.0 μg Hg/g) and a UV–visible spectrometry detection limit of 0.6 μM (equivalent to 120 ng Hg/g). The proposed method has been successfully used to detect CH₃Hg⁺ and C₂H₅Hg⁺ in fish muscle samples with a recovery of 101–109% and a RSD (n = 6) < 8%. The success of this study provided a potential method for the specific and on-site detection of CH₃Hg⁺ and C₂H₅Hg⁺ in seafood by only bare eye observation.

中文翻译：

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基于DNA模板化合金Ag-Au纳米颗粒的鱼肉中的甲基汞和乙基汞的特异和视觉检测

甲基汞（CH ₃ Hg ⁺）和乙基汞（C ₂ H ₅ Hg ⁺）的毒性比Hg ²⁺高得多，并且有机物更容易积聚以形成严重的生物扩增。因此，海产品中CH ₃ Hg ⁺和C ₂ H ₅ Hg ⁺的特异和现场检测具有重大意义和艰巨的挑战。本文我们设计两个富T-适体（H _T5和H _T7），用于特异性识别CH ₃汞柱⁺，总的CH ₃汞柱⁺和C ₂ H ₅ Hg ⁺。在所有Au ³⁺，Ag ⁺和富含T的适体存在下，CH ₃ Hg ⁺和C ₂ H ₅ Hg ⁺特异并优先与适体结合，从而在还原后诱导形成Ag-Au合金纳米颗粒，从而导致溶液颜色改变。这为无仪器视觉识别和检测CH ₃ Hg ⁺和C ₂ H ₅ Hg ⁺提供了一个传感平台。通过使用H _T5作为探针，该方法可用于通过肉眼观察检测低至5.0μM（相当于1.0μgHg / g）的CH ₃ Hg ⁺和0.5μM（相当于100 ng Hg / g）的CH ₃ Hg ⁺通过紫外可见光谱法。通过使用H _T7作为探针，该方法可用于检测CH ₃ Hg ⁺和C ₂ H ₅ Hg ⁺的总浓度，目视检测极限为5.0μM（相当于1.0μgHg / g），并且具有UV-可见光谱检测极限为0.6μM（相当于120 ng Hg / g）。该方法已成功用于检测CH ₃ Hg ⁺和C鱼肉样品中₂ H ₅ Hg ⁺的回收率为101–109％，RSD（n = 6）<8％。这项研究的成功为仅通过肉眼观察就可以对海鲜中的CH ₃ Hg ⁺和C ₂ H ₅ Hg ⁺进行特异性和现场检测提供了一种潜在的方法。